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Abstract:

The present invention is directed to a non-deforming contact lens for
keratoconus patients comprising a central zone having a displaced central
zone. In particular, the central zone is displaced from the geometric
center of the lens. The shape of the central zone is egg or spoon-shaped
and is rotationally asymmetrical with one semi-meridian that is shorter
than a corresponding semi-meridian. An intermediate transition zone is
formed integral with the periphery of the central zone, and a peripheral
zone is formed integral with the periphery of the intermediate transition
zone, forming a round contact lens.

Claims:

1. A contact lens for keratoconus, comprising:a central zone displaced
from a geometric center of the contact lens, wherein the central zone has
a substantially oval curvature and a substantially oval perimeter,
wherein the central zone is rotationally asymmetrical having a first
meridian with a semi-meridian shorter in radius than a corresponding
semi-meridian of a second meridian; andan intermediate transition zone
formed integral with a periphery of the central zone; anda peripheral
zone formed integral with a periphery of the intermediate transition
zone, wherein the peripheral zone terminates at a lens edge.

2. The contact lens for keratoconus of claim 1, wherein one semi-meridian
is lower in eccentricity than the other semi-meridian.

3. The contact lens for keratoconus of claim 1, wherein the eccentricity
of the semi-meridians are substantially equivalent.

4. The contact lens for keratoconus of claim 1, wherein the semi-meridians
are unequal in eccentricity and have radii longer than a shortest
semi-meridian.

5. The contact lens for keratoconus of claim 1, wherein at a junction of
the central zone and the intermediate zone, sagittal height is
circumferentially equivalent.

6. The contact lens for keratoconus of claim 1, wherein at a junction of
the central zone and the intermediate zone, sagittal height has a
prescribed deviation from equivalent sagittal height.

7. The contact lens for keratoconus of claim 1, further comprising:an
anterior lens surface containing a correction for neutralizing low and
higher order aberrations of a lens-eye system, wherein the correction for
neutralizing low and higher order aberrations is calculated to produce a
specific spherical aberration.

10. The contact lens for keratoconus of claim 1, further comprising an
encapsulated rigid lens for a bifocal or multifocal correction.

11. A kit of contact lenses for keratoconus, comprising:at least two
contact lenses, each lens having a posterior surface with a central zone
displaced from a geometric center of the lens, wherein a series of zones
provide a range of curvatures and substantially oval zone diameters, and
wherein an anterior surface of the lens creates lens powers respective to
the posterior zone radii.

12. A method of fitting a contact lens for keratoconus,
comprising:determining a central keratometry measurement of a patient's
eye;using the central keratometry measurement to determine an apical
radius of the contact lens;using the central keratometry measurement to
determine an amount of displacement of an apex of a cornea of the eye;
andbasing an anterior surface geometry of the contact lens on known mean
biometric values.

13. A method of fitting a contact lens for keratoconus,
comprising:determining a central keratometry measurement of a patient's
eye;measuring a horizontal iris diameter of the eye;determining a
sagittal height of a cornea of the eye from a cornea-sclera junction to
an apex of the cornea using the central keratometry measurement and the
horizontal visible iris diameter;determining an amount of displacement of
an apex of the cornea; anddetermining an anterior curvature of the
contact lens using the sagittal height, the central keratometry
measurement, the horizontal visible iris diameter, and the displacement
of the apex of the cornea.

14. The method of claim 13 further comprising:determining a bifocal
correction.

15. The method of claim 13 further comprising:determining a multifocal
correction.

16. The method of claim 13 further comprising:determining a correction for
neutralizing low and higher order aberrations, calculated to produce a
specific spherical aberration.

Description:

FIELD OF THE INVENTION

[0001]The present invention relates generally to contact lenses and
ophthalmic methods. More particularly, the present invention relates to
devices and methods for contact lenses for fitting patients with
keratoconus.

BACKGROUND OF THE INVENTION

[0002]Humans see through the cornea, the clear central part of the front
surface of the eye. Normally the cornea is dome shaped. Sometimes,
however, the structure of the cornea is not strong enough to hold the
dome shape and bulges outward in a cone shape. When this occurs, the
condition is called keratoconus. Keratoconus is a progressive disease
characterized by a thinning of the cornea with concomitant change in the
shape of the corneal surface with resultant manifestation of irregular
astigmatism and reduced best spectacle corrected visual acuity. The
progressive thinning frequently results in severe ectasia, corneal
scarring, and visual compromise that requires penetrating keratoplasty to
restore vision.

[0003]The cause of keratoconus is unknown. It may run in families and does
occur more often in people with certain medical problems, including
certain allergic conditions. Keratoconus usually begins in the teenage
years, but can begin as late as age thirty. Changes in the shape of the
cornea occur gradually, often over several years. Over time, the
patient's vision slowly becomes distorted. Both eyes are eventually
affected, even though at first only one eye may be affected. The extent
of change may vary between the eyes. Diagnosis is made using corneal
measurements.

[0004]A new spectacle can make vision clear in mild cases of keratoconus.
Eventually it will probably be necessary to use contact lenses to make
vision clear. Typically, rigid contact lenses are used. Contact lenses
manufactured for keratoconus have used posterior designs that are
geometrically centered in the lens. In the majority of keratoconus cases
the apex of the ectatic cornea is not centered, rather, it is displaced,
or off-center. Because of this, lenses designed to conform to the shape
of the cornea displace in the direction of the apex displacement as the
lenses attempt to fit the underlying cornea. Rigid contact lenses are
frequently used to provide a uniform optical surface and normal best
corrected visual acuity. At the same time, lens intolerance or scarring
may occur with these lenses. Hybrid (rigid center-hydrogel skirt) lenses
have been suggested as an ideal means of providing the benefits of rigid
lenses for correction of the irregular astigmatism by way of the tear
lens while providing the comfort and stability of soft lenses.

[0005]Recent animal research with lenses designed for purposeful corneal
reshaping and corneal refractive therapy demonstrate the potential to
increase the thickness of the epithelium with lenses that vault a portion
of the cornea. These studies explain the clinical phenomena of correcting
hyperopia by applying an lens having a radius of curvature greater than
that of the underlying cornea.

[0006]There is no evidence in the literature that any contact lens design
strategy has been useful in correcting keratoconus by therapeutically
increasing the thickness of the epithelium or the underlying cornea by
vaulting the cornea. Such a strategy would be difficult with conventional
rigid gas permeable or hydrogel contact lenses. The preferred fitting
method for rigid gas permeable lenses has been a three point of feather
touch of the lens where the lens makes direct contact with the apex or
thinnest portion of the cornea in an eye with keratoconus. In hydrogel
lenses, the lens often drapes the cornea and makes contact with the
majority of its surface.

[0007]Attempts have been made to use corneal topography to create a lens
that matches the shape of the patient's cornea. In cases or moderate to
severe ectasia, these measurements are not reliable and lenses made using
these measurements have been known to cause discomfort. The discomfort in
turn causes the patient to discontinue wearing the lenses. In addition,
corneal topography is approximately limited to the central nine
millimeters of the cornea. A well-fitted contact lens for keratoconus
must cover a larger area, preferably an area that extends beyond the
diameter of the cornea.

[0008]Soper, McGuire and Rose K lenses have been commonly used in treating
keratoconus patients. These lenses are rigid corneal lenses that are
small in diameter, rotationally symmetrical, and use multiple concentric
spherical curves. The lenses displace in the direction of the apex of the
underlying cornea and provide limited visual acuity due to the residual
low order astigmatism and higher order aberrations. Furthermore, the
lenses are time consuming to fit and provide limited comfort, wearing
time, and vision.

[0009]Another design used in keratoconus patients is the Quadra design.
This design is a rigid corneal lens with a central apex having different
eccentricities in the four quadrants of the posterior surface of the
lens. The different eccentricities in the four quadrants accommodate the
difference in sagittal height of the ectatic cornea. The Quadra design
fits the cornea more closely than lenses using concentric spherical
curves. Unfortunately, the Quadra lens also displaces toward the apex of
the cornea and provides limited visual acuity and comfort.

[0010]Softperm and SynergEyes KC are hybrid contact lenses having
spherical and elliptical concentric designs, respectively. The hybrid
lenses have a rigid gas permeable center and a soft hydrogel skirt. They
are fitted with a central or apical radius shorter than the underlying
eye and are designed to vault the apex of the cornea. The hydrogel skirt
provides better comfort than purely rigid contact lenses, but still
causes discomfort and may exhibit flexure with resulting residual low and
higher order aberrations on eyes with moderate to severe ectasia.

[0011]The Boston Scleral Lens is a rigid gas permeable lens that is custom
fitted. The lens has a central portion that vaults the ectatic cornea.
The mid-peripheral and peripheral portion of the lens align the
corneal-scleral junction and sclera. This lens design does not displace
toward the corneal apex. Fewer residual low and higher order aberrations
are found in this scleral lens-eye system, but fitting is quite complex
and expensive, leading to limited use of the design. A further drawback
is that the lenses are difficult to apply and remove and have been found
to be less comfortable than hybrid and soft contact lenses.

[0012]The Roffman lens is a hybrid multifocal contact lens incorporating
both soft lens material and a rigid lens material. The rigid lens
material is wholly contained within the soft lens material. At least one
portion of the lens, preferably the front surface, has a multifocal
optical zone. The multifocal zone may be a progressive power zone or may
contain three to five concentric zones. A drawback to the Roffman lens is
that is does not treat keratoconus and as a result would be likely to
displace in the direction of the apex of the underlying cornea.

[0013]The conventional fitting method for rigid gas permeable lenses is a
three point of feather touch of the lens where the lens makes direct
contact with the apex or thinnest portion of the cornea in an eye with
keratoconus. In hydrogel lenses the lens often drapes the cornea and
makes contact with the majority of its surface. In many cases, these
lenses are not comfortable for the patient, with the result that the
lenses are not worn.

SUMMARY OF THE INVENTION

[0014]In view of the above-identified drawbacks, the present invention
provides a design-based system of fitting the keratoconic cornea that
respects the displacement of the apex of the cornea and does not rely on
corneal topography to generate a posterior surface lens design. In
addition, the invention involves a lens for keratoconus patients that
provides increased comfort and improved visual acuity. Furthermore, the
invention provides a kit of lenses having posterior surfaces with a
displaced central zone for the correction of keratoconus, where the
series of zones provide a range of curvatures and zone diameters and the
anterior surfaces creates lens powers respective to the posterior zone
radii.

[0015]According to an embodiment of the present invention, a contact lens
for keratoconus is provided. The lens is designed to accommodate the
displaced apex of the cornea in keratoconus. This central zone of the
lens is displaced from a geometric center of the lens. The central zone
has an oval curvature, being egg- or spoon-shaped. This central zone is
rotationally asymmetrical with one semi-meridian being shorter than a
corresponding semi-meridian. An intermediate transition zone is disposed
outside the central zone of the lens. In turn, this intermediate
transition zone terminates in a peripheral zone. The peripheral zone
terminates at the lens edge, providing a round contact lens.

[0016]An additional embodiment provides a kit of contact lenses for
fitting patients with keratoconus. The kit includes at least two contact
lenses for keratoconus. Both sets of contact lenses have posterior
surfaces with displaced central zones. Each central zone provides a range
of curvatures and zone diameters. The anterior surfaces create contact
lens powers respective to their posterior zone radii.

[0017]The invention also provides a method of fitting a contact lens for
keratoconus. The method includes the step of determining a central
keratometry measurement. This central keratometry measurement is used to
determine an apical radius of the contact lens for keratoconus. In
addition, the central keratometry measurement is used to determine the
amount of displacement of the apex of the patient's cornea. These
measurements are used to determine an anterior surface geometry using
known biometric values.

[0018]An additional embodiment provides for another method of fitting a
contact lens for keratoconus. The embodiment involves determining a
central keratometry measurement and also measuring a horizontal iris
diameter. The sagittal height of the cornea from a cornea-sclera junction
to an apex of the cornea using the central keratometry measurement and
the horizontal visible iris diameter. A further step in the method
involves determining an amount of the displacement of the apex of the
cornea.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is an anterior view of a contact lens for keratoconus
according to an embodiment of the invention.

[0020]FIG. 2 is a side view of a contact lens for keratoconus according to
an embodiment of the invention.

[0021]FIG. 3 is an anterior view of a contact lens for keratoconus
incorporating bifocal or multifocal correction according to an embodiment
of the invention.

[0022]FIG. 4 is a side view of a contact lens for keratoconus
incorporating embedded bifocal or multifocal correction according to an
embodiment of the invention.

[0023]FIG. 5 is an anterior view of a contact lens for keratoconus
according to an embodiment of the invention.

DETAILED DESCRIPTION

[0024]In the following paragraphs, the present invention will be described
in detail by way of example with reference to the attached drawings.
Throughout this description, the preferred embodiment and examples shown
should be considered as exemplars, rather than as limitations on the
present invention. As used herein, the "present invention" refers to any
one of the embodiments of the invention described herein, and any
equivalents. Furthermore, reference to various feature(s) of the "present
invention" throughout this document does not mean that all claimed
embodiments or methods must include the referenced feature(s).

[0025]As set forth hereinabove, prior art contact lenses for keratoconus
used posterior designs that were geometrically centered on the contact
lens. However, in the majority of cases of keratoconus, the apex of the
cornea is not centered, rather, it is displaced from the center. Lenses
conforming to the shape of the cornea are displaced in the direction of
the apex of the cornea.

[0026]Corneal topography has been used in attempts to create lenses to
precisely match the shape of the underlying cornea. For moderate to
severe ectasia, the measurements are not reliable and lenses produced
using the measurements are uncomfortable to wear, especially for long
periods. This discomfort causes patients to discontinue wearing the
lenses. In addition, corneal topography is limited to measuring the
central nine millimeters of the cornea, not enough to ensure a
well-fitting lens. Further, gravity and lid interaction forces cause the
lens that is intended to match the corneal surface to misalign with
resultant unanticipated aberrations and reduced visual acuity.

A. Devices of the Present Invention

[0027]Referring now to the figures, which are illustrative of multiple
embodiments of the present invention only and are not for purposes of
limiting the same, FIG. 1 depicts a contact lens 100 for keratoconus in
accordance with one embodiment of the present invention. The keratoconus
contact lens 100 of the invention has a displaced central zone 102 that
is offset from the geometric center 118 of the lens 100. The curvature of
the central zone 102 is substantially oval in shape in that it resembles
the curvature of a spoon or a hen's egg, and the perimeter 104 of the
central zone 102 also takes the shape of a spoon or a hen's egg in the
plane of the lens 100. The perimeter 104 of the lens 100 also forms a
junction between the central zone 102 and an intermediate transitional
zone 106.

[0028]With further reference to FIG. 1, the displaced central zone 102 is
rotationally asymmetrical with a first meridian 114 having a
semi-meridian that is shorter in radius (or lower in eccentricity) than
the corresponding semi-meridian of a second meridian 116. The two
semi-meridians are 90 degrees apart and may be equal or unequal to each
other in eccentricity. Additionally, these semi-meridians may have radii
that are longer than the shortest semi-meridian.

[0029]With continued reference to FIG. 1, the central zone 102 is integral
with the intermediate transitional zone 106 that terminates at a junction
108, wherein the lens 100 may be circumferentially equivalent in sagittal
height or the lens 100 may have a predetermined deviation from the
equivalent sagittal height. The intermediate zone 106 of the lens is
integral with a peripheral zone 110 that terminates at a lens edge 112 or
perimeter to form a round lens shape.

[0030]FIG. 2 illustrates a side view of the contact lens for keratoconus
of FIG. 1 according to an embodiment of the invention, wherein like
elements have been numbered accordingly. In the illustrated embodiment,
R1 is the local radius of the middle portion of the central zone 102, R2
is the local radius of the intermediate transition zone 106, and R3 is
the local radius of the peripheral zone 110.

[0031]The contact lenses described herein may be manufactured from a rigid
gas permeable material or a soft lens material, such as hydrogel. As
would be understood by those of ordinary skill in the art, other
materials may be used to manufacture the lenses without departing from
the scope of the invention. Additionally, the lenses may have a soft or
flexible edge, as well as other features designed to improve comfort, and
hence, wearing time of the lenses.

B. Methods of Fitting

[0032]A continuum of methods of fitting may be utilized to fit the contact
lens 100 for keratoconus. Eye care practitioners are trained to use a
central keratometry measurement to determine the suggested radius of
curvature for rigid and soft contact lenses. This value may be used to
fit an embodiment of the lens 100 of the invention, wherein the central
keratometry value determines the apical radius of the lens and the
anterior surface geometry is based on the known mean biometric values.

[0033]A more complex method may utilize the central keratometry value and
the measured value of the horizontal visible iris diameter. These two
factors assist in the determination of the sagittal height of the cornea
from the cornea-sclera junction to the apex of the cornea, and also
determine the location of the apex of the cornea.

[0034]Corneal topography may also be used to determine the apical radius
and the average eccentricity to the widest accurate chord diameter along
with the horizontal visible iris diameter. In this manner the mathematics
of the central elliptical and parabolic zones of the progressive geometry
may be refined. Rasterizing and Fourier methods used in topography may be
useful to provide additional biometric data beyond the chord diameter of
the data provided by placido based methods.

[0035]In addition, optical coherence tomography may be employed to
determine the progressive geometry of the cornea, the cornea-scleral
junction, the location of the apex of the cornea and the geometry of the
anterior surface of the lens.

[0036]Once the posterior geometry of the lens is determined, the anterior
curvature of the lens may be calculated using the posterior apical
radius, the index of refraction, the known manifest refraction and the
vertex distance used in the manifest refraction. Higher order aberration
correction for that induced by the posterior geometry may be added to the
anterior surface geometry.

C. Alternative Embodiments

[0037]An additional embodiment of the invention also provides for a kit of
lenses 100 having posterior surfaces with a central zone 102 displaced
from the geometric center of the lens 118, for correction of keratoconus.
The series of zones contained within the lens 100 provide a range of
curvatures and zone diameters and the anterior surface of the lens 100
creates lens powers respective to the posterior zone radii.

[0038]According to an embodiment of the contact lens 100 for keratoconus,
the posterior curvature of the two principle meridians (that are 90
degrees apart) varies according to the local geometry in each meridian.
Each meridian includes a geometry based on the apical radius of the
respective meridian.

[0039]A further embodiment of the invention is depicted in FIG. 3.
Specifically, a contact lens 300 for keratoconus provides for bifocal or
multifocal correction. In the illustrated embodiment, the contact lens
300 features the same back surface geometry as the single vision
(non-bifocal) designs. Accordingly, the bifocal or multifocal correction
is equivalent to the correction in the single vision lens of FIGS. 1 and
2. This bifocal or multifocal correction is incorporated in the anterior
surface of the lens 300 or encapsulated within the lens. The correction
has center and peripheral zones that are comprised of multiple spherical
curvatures, or a combination of spherical and aspherical curvatures. The
size of the central and peripheral zones may be determined by pupil size
or any other arbitrary means, and may take into account an off-center
location of the apex of the cornea. The central zone may be displaced
from the geometric center of the lens to compensate for the deviation of
the apex of the cornea from the center of the eye and to prevent the lens
300 from displacing toward the apex of the cornea.

[0040]With continued reference to FIG. 3, the lens 300 is similar in some
regards to the lens 100 of FIGS. 1 and 2, and like elements have been
labeled accordingly. Similar to previous embodiments, the lens 300
includes a central zone 102' and an intermediate zone 106' that meet at a
junction 104', and a peripheral zone 110' that meets the intermediate
zone 106' at a junction 108'. The geometric center 118' is offset from
the central zone 102'.

[0041]With further reference to FIG. 3, the bifocal or multifocal
correction is incorporated in the anterior surface of the lens 300, as
shown by element 318 located in the central zone 102'. The area of
correction 318 may have a center near or center distance design.
Additionally, the central zone 102' and peripheral zone 110' may comprise
multiple spherical curvatures, two aspherical curvatures, or a
combination of aspherical and spherical curvatures. The size of the
central zone 102' and peripheral zone 110' may be determined by pupil
size or by arbitrary means. The central zone 102' is displaced from the
geometric center 118 of the lens 300 to compensate for the deviation of
the geometric center of the lens 300 from the center of the pupil or the
deviation of the geometric center of the lens 300 from the line of sight.

[0042]FIG. 4 shows a further embodiment incorporating bifocal or
multifocal correction. In this embodiment, the bifocal or multifocal
correction is encapsulated within the lens 400, as shown by element 414
located in the central zone 102''. The area of correction may have a
center near or center distance design. The central zone 102'' and
peripheral zone 110'' may comprise multiple spherical curvatures, two
aspherical curvatures, or a combination of aspherical and spherical
curvatures. The size of the central zone 102'' and peripheral zone 110''
may be determined by pupil size or by arbitrary means. The central zone
102'' incorporating the embedded bifocal or multifocal correction 414 is
displaced from the geometric center of the lens 400 to compensate for the
deviation of the geometric center of the lens 400 from the center of the
pupil or the deviation of the geometric center of the lens 400 from the
line of sight.

[0043]FIG. 5 shows a further embodiment incorporating a junction 108''' of
the intermediate zone 106''' and peripheral zone 110'''. Intermediate
zone 106''' contains a central zone 102''' that is asymmetrical. The
intermediate zone 106''' accommodates the rotational asymmetry of the
central zone 102''' to create symmetry and a circumferentially equal
sagittal height at 108'''.

[0044]A still further embodiment provides for correction of higher order
aberrations of the lens-eye system. The lens-eye system may have higher
order aberrations that result from the aberrations of the eye, the
aberrations of the lens and the aberrations from the position of the lens
on the eye. The lens may induce new aberrations into the lens-eye system.
One method of determining the residual lens-eye aberrations is to conduct
an over-refraction test using an aberrometer. In this manner, the
anterior or posterior surface of the lens may be modified to correct
residual lens-eye aberrations.

[0045]The most significant aberration of the modal lens-eye system is
spherical aberration. Spherical aberration may be corrected without the
use of over-refraction with an aberrometer. The spherical aberration of
the eye is measured by conventional means using the aberrometer, and the
spherical aberration of the lens is calculated by conventional means
using the apical radius and conic constant over the central zone of the
posterior surface and the lens power. The anterior curvature may then be
calculated to produce the desired spherical aberration of the lens-eye
system. In some cases the desired amount may be zero or the lens-eye
system may be best corrected with a prescribed amount of positive
spherical aberration.

[0046]Thus, it is seen that contact lenses for keratoconus and methods for
fitting such lenses are provided. One skilled in the art will appreciate
that the present invention can be practiced by other than the various
embodiments and preferred embodiments, which are presented in this
description for purposes of illustration and not of limitation, and the
present invention is limited only by the claims that follow. It is noted
that equivalents for the particular embodiments discussed in this
description may practice the invention as well.

[0047]While various embodiments of the present invention have been
described above, it should be understood that they have been presented by
way of example only, and not of limitation. Likewise, the various
diagrams may depict an example architectural or other configuration for
the invention, which is done to aid in understanding the features and
functionality that may be included in the invention. The invention is not
restricted to the illustrated example architectures or configurations,
but the desired features may be implemented using a variety of
alternative architectures and configurations. Indeed, it will be apparent
to one of skill in the art how alternative embodiments may be implemented
to achieve the desired features of the present invention. Also, a
multitude of different constituent part names other than those depicted
herein may be applied to the various parts of the devices. Additionally,
with regard to operational descriptions and method claims, the order in
which the steps are presented herein shall not mandate that various
embodiments be implemented to perform the recited functionality in the
same order unless the context dictates otherwise.

[0048]Although the invention is described above in terms of various
exemplary embodiments and implementations, it should be understood that
the various features, aspects and functionality described in one or more
of the individual embodiments are not limited in their applicability to
the particular embodiment with which they are described, but instead may
be applied, alone or in various combinations, to one or more of the other
embodiments of the invention, whether or not such embodiments are
described and whether or not such features are presented as being a part
of a described embodiment. Thus the breadth and scope of the present
invention should not be limited by any of the above-described exemplary
embodiments.

[0049]Terms and phrases used in this document, and variations thereof,
unless otherwise expressly stated, should be construed as open ended as
opposed to limiting. As examples of the foregoing: the term "including"
should be read as meaning "including, without limitation" or the like;
the term "example" is used to provide exemplary instances of the item in
discussion, not an exhaustive or limiting list thereof; the terms "a" or
"an" should be read as meaning "at least one," "one or more" or the like;
and adjectives such as "conventional," "traditional," "normal,"
"standard," "known" and terms of similar meaning should not be construed
as limiting the item described to a given time period or to an item
available as of a given time, but instead should be read to encompass
conventional, traditional, normal, or standard technologies that may be
available or known now or at any time in the future. Likewise, where this
document refers to technologies that would be apparent or known to one of
ordinary skill in the art, such technologies encompass those apparent or
known to the skilled artisan now or at any time in the future.

[0050]A group of items linked with the conjunction "and" should not be
read as requiring that each and every one of those items be present in
the grouping, but rather should be read as "and/or" unless expressly
stated otherwise. Similarly, a group of items linked with the conjunction
"or" should not be read as requiring mutual exclusivity among that group,
but rather should also be read as "and/or" unless expressly stated
otherwise. Furthermore, although items, elements or components of the
invention may be described or claimed in the singular, the plural is
contemplated to be within the scope thereof unless limitation to the
singular is explicitly stated.

[0051]The presence of broadening words and phrases such as "one or more,"
"at least," "but not limited to" or other like phrases in some instances
shall not be read to mean that the narrower case is intended or required
in instances where such broadening phrases may be absent.